Directions:

Preheat oven to 350°F (177°C). Line a 12-count muffin pan with cupcake liners. This recipe makes 14 cupcakes, so you will have 2 cupcakes to bake in a 2nd batch. Please read notes about mini cupcakes.

Make the cupcakes: With a handheld or stand mixer fitted with a whisk attachment, beat 2 egg whites on high speed in a medium bowl until soft peaks form, about 2-3 minutes. See photo at the bottom of this post for a visual. Set aside.

Sift the flour and cornstarch together to make sure it is evenly combined. Whisk this, along with baking soda, cocoa powder, and salt together in a medium bowl. Set aside.

Using a handheld or stand mixer fitted with a paddle attachment, beat the butter on high speed until smooth and creamy - about 1 minute. Add the sugar and beat on high speed for 2 minutes until creamed together fairly well. Scrape down the sides and up the bottom of the bowl with a rubber spatula as needed. Add the oil and beat on high for 2 minutes. The butter may look "piece-y" and not completely combine with the oil. This is normal and ok.

Add 2 egg yolks and the vanilla. Beat on medium-high speed until combined. Scrape down the sides and up the bottom of the bowl with a rubber spatula as needed. Beat in the vinegar and the food coloring-- until you reach your desired color. I use 2 Tablespoons. With the mixer on low speed, add the dry ingredients in three additions alternating with the buttermilk, beginning and ending with the dry ingredients, and mixing each addition just until incorporated. Do not overmix. Fold whipped egg whites into cupcake batter with a rubber spatula or wooden spoon. The batter will be silky and slightly thick. (If there are still pieces of butter - and there were in 1 test batch for me - again, this is ok. They will melt inside as the cupcakes bake. Making them even more buttery.)

Spoon batter into cupcake liners filling 1/2 - 2/3 of the way full. Bake for 20-21 minutes or until the tops of the cupcakes spring back when gently touched and a toothpick inserted in the center comes out clean. Don't overbake; your cupcakes will dry out. Allow to cool in the pan for 5 minutes, then transfer to a rack to cool completely.

Make the frosting: In a medium bowl using a handheld or stand mixer fitted with a paddle attachment, beat the cream cheese and butter together on medium speed until smooth, about 2 minutes. Add the confectioners’ sugar and 1 Tablespoon cream. Beat for 2 minutes. Add the vanilla and 1 more Tablespoon cream if needed to thin out. Beat on high for 1 full minute. Taste the frosting and add a pinch of salt if too sweet. Frost cooled cupcakes immediately before serving. I used a Wilton #12 tip; I don't recommend a star tip. This frosting is a little too thin.

Additional Notes:

I use a combination of sifted flour + cornstarch to produce cake flour - if you keep cake flour in the pantry, use 1 and 2/3 cups (192g) instead of the specified all-purpose flour and cornstarch.

The amount of red food coloring is up to you. I tested with varying amounts. To get the dark red color you see here, use 2 Tablespoons of liquid food coloring. Dye the batter until you are pleased with the color. Of course, you don't have to dye the batter at all if you don't want to. I have never tested this recipe with a natural alternative.

Buttermilk is required. I use low-fat because that's what I typically have, but full fat buttermilk is fine here. If you do not have buttermilk, make your own by mixing 1 teaspoon white vinegar or lemon juice with 1/2 cup milk. Stir and let sit for 5 minutes.